Don't ride the same model Vado, but my Vado 5 speed sensor magnet is embedded in the rear hub. I can't see the sensor, but I believe it is in the mount for the brake caliper based on wire routing and the 'divot' in the caliper mount.
I have the Vado SL 5 EQ. There are magnets imbedded in the rear brake rotor. The sensor appears to be be below the brake caliper, like Tim’s bike, part of the caliper mount.