How should I organize network and power cables ?

When you coil copper wire together into a large bundle you are actually making an antenna, which can cause interference, causing havoc in wireless network signals, as well as unshielded network cables. Your goal in cable organization should be to minimize the number of times that any cable crosses any other cable. Running your cables at 90-degree angles, and keeping them to a minimum length to prevent coils will help ensure there is as little interference to the signal as possible.

Also, try keeping network cables separate from any source of possible interference, including power cables, UPS backups, even some cable/dsl modems, routers, switches as much as feasible. In industrial applications, major sources of interference are fluorescent lights, electrical motors, air conditioners, microwaves, refrigerators, etc.

In theory, any adjacent electrical device or cable can potentially introduce EMI interference.