You can modify the appearance of streams and their labels, change the appearance of stream junctions and stream nodes, and set the visualization scale for the Stream Alignment layer. From the Map Layers editor, right-click on Stream Alignment and from the shortcut menu, click Properties. The Stream Alignment Properties dialog will open.

Stream Alignment Properties Dialog

Streams

You can change the appearance of streams in the stream alignment to best suit your needs. 

Width

You can set the width of the lines that represent streams from the Stream Width dropdown menu.
Stream Alignment Properties - Streams

Color

You can select the color of the lines that represent the streams from the Stream Color dropdown menu. The default color is orange. There are several colors to choose from, but you can also create custom colors.

From the Stream Color list, click Custom. The Choose A Color dialog will open. See Using the Color Chooser for further details.
Choose A Color Dialog

A preview of the stream color changes is shown in the Stream Alignment Properties dialog. Click Apply to apply the changes.
Preview Stream Color Changes

Labels

By default, stream labels appear in the map window. If you do not want the labels displayed, from the Stream Alignment Properties dialog, uncheck Show Stream Name and click Apply.

To change the font of the stream labels, from the Stream Alignment Properties dialog, click Choose Font. The Font Chooser dialog will open. Select the font type from the Font list, and select a size using the Size slider. Click OK, and the Font Chooser dialog will close. Click Apply on the Stream Alignment Properties dialog. All stream labels will now appear with the settings you chose.
Font Chooser Dialog

Tic Marks

Tic marks appear on a stream representing the stream stationing. There are two types of tic marks, minor and major. 

If you do not want to display the tic marks, from the Stream Alignment Properties dialog, uncheck Draw Station Tics and click Apply.
Stream Alignment Properties - Tic Marks

From the Tic Length list, you can set the length of the minor tic marks. To change the length of the major tic marks, use the Major Tic Length list. Click Apply, and the map window displaying the stream alignment will update.

To change the font of the tic mark labels, from the Stream Alignment Properties dialog, click Choose Font. The Font Chooser dialog will open. Select the font type from the Type list, and select a size using the Size slider. Click OK, the Font Chooser dialog will close. From the Stream Alignment Properties dialog, click Apply. All the tic mark labels will appear with the settings you chose.

Stream Nodes

If you do not want to display stream nodes, from the Stream Alignment Properties dialog uncheck Draw Stream Nodes and click Apply.
Stream Alignment Properties - Stream Nodes

You can select the color for stream nodes from the Node Color list. The default color is green. Similar to streams, you can also create a custom color.

You can select the outline color of stream nodes from the Node Outline Color list. The default color is dark green. Similar to streams, you can also create a custom color.

You can set the width of stream nodes from the Node Width list.

Junctions

If you do not want to display stream junctions, from the Stream Alignment Properties dialog uncheck Draw Junctions and click Apply.
Stream Alignment Properties - Stream Junctions

You can select the color of stream junctions from the Junction Color list. The default color is dark green. Similar to streams, you can also create a custom color.

You can set the width of Stream Junctions from the Junction Width list.

Scale

The visualization Scale feature allows you to customize stream alignment display settings as you zoom in and out on the map window. 

To set the visualization scale for the stream alignment to a default, from the Stream Alignment Properties dialog, click Scale and then click Set to Defaults. The visualization scale is set automatically.

To enter your own scale factor, from the Stream Alignment Properties dialog, click Scale and then click New. The Create New Scale Dialog dialog will open. In the Scale box, enter values for the scale factor.
Create New Scale Dialog

Click OK. This creates a new tab in the Stream Alignment Properties dialog. From the new tab, you can configure the stream alignment's appearance.