You are able to re-order employees on the Scheduler with four options. To do this, on the Scheduler go to View and you'll see the list of options.
This is customisable on each manager's account, meaning you can have one version and another manager in the same store can choose another.
Position
This will schedule users by Position, followed by contract type and finally alphabetical
First Name
This will schedule users by First Name alphabetically
Last Name
This will schedule users by Last Name alphabetically
Contracted Hours
This will schedule users by contracted hours