Yes, that cable option should be fine. I’ve made my own waterproof housing for the sensor end using a threaded PVC coupler and a cable gland since that’s cheaper. You won’t need a 6-pin screw terminal since there’s only 3 wires to connect (power, ground, and data). You can connect a 4th line to the start/stop pin of the sensor if you want to trigger the readings that way, but it’s not necessary. So just a regular Grove-to-4-terminal board would work fine for connecting it to one of the Mayfly’s Grove ports.