You mentioned having solid catsuits in the past - I'm not sure if you patterned these or bought them, but for the sake of this post I'll assume you have a pattern for a bodysuit (if not, http://www.stretchy.org/
has lots of tutorials).
Anyway, if you want to do all those shapes through seams (I'd recommend doing them as seams or as applique, since paint won't stretch and if you try it'll probably just crack) it's actually very simple to add those seams. Just take the pattern, draw lines where you want the seam to be (essentially just draw her costume's design onto the pattern), cut it along those lines, tape the cut line down on some paper, and add some seam allowance onto it (just draw another line running along the outside, commercial patterns usually use around 3/8", personally I use 1/2", whatever you tend to use when you're sewing). Then just cut it along that outer line and voila, you have new pattern pieces!
BTW, when you sew spandex (especially like this if you have lines running across the suit) you should either use a stretch stitch, a serger, or a zigzag stitch so it can still stretch along the seam!