I need a diagram of the atx pwr connector for an ASUS P4V8X-MX

If you mean power to the devices themselves, the 4-pin connectors coming from the power supply plug in to the drives. The red wire is +5 volts, the yellow wire is +12 volts and the black wires are ground (earthing) connections. IDE hard drives and CD drives use the same connector. SATA drives may have that same connector as well, but most use a different style. SATA-ready power supplies will have 1 or more plugs available. Adapters to switch from the 4-pin IDE plug to SATA type are available for supplies that don't have the right connector.

If you are asking what power pins from the mainboard power supply connector are supplying power to specific controller parts on the mainboard, that kind of detailed information is not available. Mainboards manufacturers do not supply circuit diagrams or repair information. They simply replace any boards that fail while still covered by the warranty, and expect you wil just buy a new one if the warranty has expired.

Much information about ATX boards including the power supply cable pins is found here:

http://en.wikipedia.org/wiki/ATX