You add it to the surface, under object properties. The color is considered a texture, also, you can add textures, like canvas cloth, etc. Like everything in Rhino, there are many ways of doing it.
Not sure why the picture on the left is so jagged. I don't know what type of computer or video card you use, that could have something to do with it.
Your panel lines are so outstanding, they could making anything look incredible! I think you have some of the best, it not the best, panel lines I have ever seen.
I tried to recreate the jagged look of that pic on the left, I couldn't, so it could be a hardware issue. Not sure how you got that pic out of Rhino either, I find printing to file yields a much better result.
