You're dealing with transmission lines for RF frequencies here, so you need to pay careful attention to characteristic impedance
to avoid reflections which will degrade signal integrity. Ethernet twisted pair is 100 ohm, while USB is 90 ohm. Close enough that it should work... most of the time... but not optimal.
You really want bulk cable that is specifically designed for USB, like this
. Or just chop the connectors off the ends of commercial USB cables.
You will also need to pay attention to the routing of the wires/traces which connect to your cable, as any deviations from 90 ohm transmission line design rules will cut into your signal integrity as well.