I used to make test fixtures. I'd draw the panel layout and add the labels in the drawing on another layer. I included center points for drilled or punched holes. I would print the drawing on 8-1/2 x 11 adhesive backed stock, which comes in many colors, including plain white. With the CAD program, you could add colored back grounds, outlines, whatever you could draw. Once drawn, I would use a hot laminater to laminate only the face of the material. (you can also get self adhesive laminating sheets) Cut it out and apply it to the panel and use the center marks and outlines to cut, drill and punch the holes for perfect alignment. The labels can be a plain or as fancy as you like. Rather than using the self adhesive paper, you could also use plain paper and hold it to the panel with a thin piece of Lexan and small screws for a more durable and oil and dirt resistant label. I'll see if I still have some photos of one of my fixtures. and post one if I do.