To get a study permit the college or Uni must be on the designated learning list http://www.cic.gc.ca/english/study/study-institutions-list.asp
It is not as simple as just attending Uni, graduating and getting a job, sure post graduation you could apply for a post grad work permit (PGWP) but that is only temporary although dependent on your course can be for upto 3 years. You would need to apply for immigration like anyone else through one of the immigration programs. Provided you maintain legal status in the country you do not need to necessarily return home
See here re post grad work permit http://www.cic.gc.ca/english/study/work-postgrad.asp