I never use Microsoft graph. I just want to query to just pull a selection of users by supervisor using Microsoft graph
Documentation for the GET /users is here.
You can "play" with the Graph API using the Graph Explorer.
You can use the odata filter to get users whose
manager property equal a certain value. Or alternatively, you can get the single user object for the supervisor, then use that user object's
directReports property to find the users that report to them.