They are supposed to centre the steering wheel before they attempt the alignment.
So, right off the hop, they did it wrong. Go back and insist they re-do it and if they can't align the steering wheel know the reason why (insist on having their explanation, or excuse, in writing on the work order).
An old and wrong way to align the vehicle is to put a right turn bias so that if the driver falls asleep, the car does not cross the centre line. It's not the right way to do it, but I suppose you could run into a tech who believes in that, so make sure it isn't deliberate.
As others have said, let it settle for 100 miles or so. You should have new tires or very good condition tires on the axle being aligned (front only or front and rear if independent suspension on all four).
Also be sure that you are not mis-reading the problem being alignment when it's the crown of the road you are feeling. A wide limited access highway (such as an interstate) in the centre of at least three lanes is probably as flat as you are going to find anywhere. Two Lane Blacktop will have a pronounced crown that will move the vehicle to either side if you take your hand off the wheel (safely, of course).
Ask in your area amongst the sports car enthusiasts (doesn't matter whom although a bunch of BMW or Porsche or MIata people are probably more tuned into alighnments than drag racers or circle track guys). They will be taking their cars to someone who does proper alighments and to either factory specs or their own. That shop will do it right (they may even have a tech sit in the drivers' seat while doing it, which is technically the proper method, but is more than is necessary for a street vehicle).
If it's a fully independent suspension, I like to have the shop align the rear axle and then do the front off of that base setup.
