XPS 8930, 9XG5C power supply, no cables?

Is the new PSU a non-modular or modular PSU?

If it's non-modular and has a wiring bundle coming out of it, you can use the cables in the bundle and whatever other cables/connectors you need from the old PSU.  If it's modular, you'll have to get new cables that plug into the PSU with connectors for your hardware.

Why are you replacing the PSU?

The 3rd image at the link you posted for Dell's 9XG5C lists caveats that it doesn't come with any cables.

Lots of threads about replacing PSU in XPS 8930 so read some of them.  Many people seem to be installing modular PSUs but you have to get the right cables that plug directly into the PSU.

You don't have to buy a new PSU from Dell. It should be a standard ATX PSU, so you should be able to find a non-modular one that works, if that's what you prefer. Just confirm the dimensions of old vs new PSU.