I ran your image through GIMP to turn it into a bitmap, then put the bitmap into Inkscape to trace it using the “Trace Bitmap” command under the “Path” menu. Removing unnecessary scans I was able to get this SVG:
I put that SVG into JSCut and performed an Engrave operation on it.
I think that should get you all the internal lines you need to do a paint by color. This is actually something that I plan to do as well, as I have a Grinch that I made by hand a couple years back and I want to use the Maslow to make his dog Max.
