This old generic controller for my PSone has seen better days from it was last playing Tony Hawks Pro Skater 2.
The wire is frayed, so I gave it a bit of an overhaul.
Disassembly is pretty simple.
It also a good idea to give the buttons and bits a good clean out off all the gunk that builds up. My friends PS3 controller was having weird random button presses, the cause of that was some dirt on the underside of one of the buttons, isopropyl is a good choice for carefully cleaning the contacts.
As the top half of the controller is transparent, I'm going to spray paint it a new colour. As always, preparation gets the best results with spray paint, so mask off all the parts you don't want paint on.
I went with some Silver Spanish Montana spray paint, apply a light even coat.
As my masking wasn't perfect, you can remove the excess with a rag and some isopropyl alcohol or white spirit.
To get to the broken section of the cable, you'll need to de-solder the cable from the board.
Remember to note down the order of the wires.
Now I've got the damaged cable off, find some heat shrink off suitable size.
You can use more than one layer to try and build up some support around the break.
Now re-solder the fixed cable back to the board and re-assemble.
The final finish didn't come out exactly as I expected, it is a little uneven in parts.
There are probably lots of designs you could paint the interior other than just a solid colour, splats, stripes, dots etc.
Second attempt on a generic USB controller for my computer
Again stripped it all down and masked off, then splattered acrylic paint.