You should be good with any portable NEMA14-50P charging cord.
Here are a few brands that should work:
40amp, 16ft cord:
Lectron Level 2 EV Charger - ETL Certified, 240V, 40 Amp, NEMA 14-50 Plug, 16 ft Extension Cord & J1772 Cable- Portable Electric Car Charger for J1772 EVs and Plug-in Hybrid...