Assuming that both the NVR and camera have RJ-45 connectors then use either CAT-5e or CAT 6 cable which are both good to 100 meters. If purchasing bulk cable make sure that it is NOT copper clad aluminum. Belden is a good reliable choice but expensive.
If doing your only cable ends (RJ-45) make sure to get the correct connectors as CAT 6 cable is slightly larger and does not fit well into a CAT 5e connectors.