Well, I use Super-O so the issues are a bit different, but maybe this will give you some ideas:
Raw Super-O switches look like this:
I start by cutting "stencils" that fit the parts of switch that I want to show, and hide the rest:
I then simply continue my ground cover seamlessly over the stencils:
You can also bury the entire switch motor in pink foam.
Similarly, I often hide the huge bakelite bases of early accessories (as well as other unrealistic bases) in foam under ground cover:
