You can apply a different color or material to edging using the Materials Paintbrush.
To apply different materials to edging:
Display your model in 3D, and make sure the edging is visible in the view.
Select Edit
> Materials Paintbrush, or click the Materials Paintbrush button
on any tabbed toolbar.
In the catalog panel, select the material you want to apply.
Click on the edging.
Right-click and select Finish.