I've got no idea how you get (for exemple) the right blue to the upper part and the right purple to the bottom part with only one way between them. I suppose I have to use the grey one attached to the blue but that doesn't make anything clear... Edit: I think I see sth.
It is not so tough actually. I put it in 'hard' category and didn't know it is in 'insane' now. It's maybe better because the solution is long and if you don't play carefull you'll have to start over.