I presume that with survivor its a win based system.
Its not STRICT in the sense that there is only one way to WIN, but yes, the main goal is to be the only one that survives while everyone else is eliminated. There are scenarios where there are multiple winners.
What happens if teams draw?
You pick a TEAM to WIN their match. A Draw is not a WIN, so if you pick Team A to win and Team A is playing Team F and they TIE (Draw), then your pick of Team A to win is incorrect and it counts as a strike. That is how Survivor works.
I presume the user gets eliminated?
That all depends on if its a single, double or triple elimination pool. Elimination is based on strikes received. If its a single elimination, then yes, however, it its double or triple elimination and its their first strike, then no.
but let's say there are 4 left standing and all teams draw, do I just split the pot?
Yes, that is how Survivor works. If you are in week 6 and there are x players still alive and all of them are eliminated, those x players would be considered the winners of the season (unless you have your own rules and tie breaking procedures).
NOTE: You can make your OWN RULES AND TIE BREAKERS (which most pools have their own rules). For example, the way WE do it, is by game time. Not all games (matches) start and end at the same time, so player x might get eliminated at 1pm, 2 more at 1:15 PM, another one at 1:30 pm and the last one at 2:05 PM (so the one at 2:05 lasted longer by the luck of the match he choose was later than the others.
You can do things like create tie breakers based on trivial things that are used to determine the overall sole survivor if you want to (and probably should if you are doing this for money).