You can leave Canada and return, as long as your visa or Electronic Travel Authorization (eTA) is still valid. Your permit (study or work) is not a visa and doesn't allow you to travel back to Canada.,
If your visa or eTA is expired, you have to get a new one before you return to Canada.,
When you return to Canada:,
A border officer will have some questions for you when you arrive back in Canada. The officer may ask you for proof that you applied for a post-graduation work permit, such as a copy of your application or the fee payment receipt.,
If the officer believes there is reason to refuse your re-entry, you won’t be able to enter Canada.