If its your stuff and you can unhook it, I would say start there. Start by like numbering the cables that you have to where they end up. so on one end put #1 and then on the other end put the same number #1. Get a piece of tape and put #1 on it and put it over the port on the device and then continue from there. That way you have the cables labeled and to what port they go to.
Then from there you can start arranging them more consistently either with the same cables or using newer ones. With how it is right now, you either have to start by unhooking it all or start by picking a device first and putting it together using the same method.