If you click the "Google Drive" link in MyCanisius (under My Applications) this will log you into your Canisius Google account.
However, if you wish to log into your Google Drive through an app on a phone or tablet, you need to log in with (username)@my.canisius.edu.
On the righthand side of your Google Drive screen you will see an email address that is (username)@my.canisius.edu. But your Google Apps for Education/Canisius Google Drive account operates with and through (username)@canisius.edu (no "my." is necessary in the address.)
However, (username)@my.canisius.edu is an identifier Google uses for your Google Drive account, and can be useful to you. This is the identity you would use to set up your Canisius Google Drive to operate through a mobile app (on either Android or iOS).