Hi pvonk -
Mainline intercity trains in Switzerland and international trains arrive at Geneva main station (Station name Cornavin) in downtown Geneva a few blocks from the lake shore.
Swiss trains, at least , continue to the airport, a journey of aproximately 10 minutes. The name of the aeroport is "Cointrin."
There have been many "upgrades" at Cornavin since I was a regular user a few years ago, so I cannot say exactly where the foreign exchange desk(s) is, or the ATM's. However, I know that they are there. And, of course, there is always a tourist info office at the main stations to direct you.
I have also used the ones on the pedestrian mall on the ramp leaving the lower part of the station which becomes Rue du Mont Blanc.
So, i looked at a map.
The map named Mapsearch.ch
is very useful for finding things of interest to tourists.
I opened it, zoomed in on the train station in Geneva, and turned on the aerial view to help orient me better. I immediately saw the "cash dispensers."
I am not sure whether this link shows the exact information I am seeing, but it shows three icons for "cash dispenser" in the station, and more on the routes to the lake.
If they do not appear, open"Points of Interest" under the Menus, and turn on the entry for "Shopping/Service."
One is a "Postomat" at the post office, and will have good rates. Another is UBS, and the third is associated with the SBB ( or, rather CFF, which are the proper initials in the French-speaking regions).
All give good rates.
Another way to find things in Swiss rail stations, especially the main ones, is to use text information and the maps available through the main SBB/CFF web site.
shows the icon and opening hours for currency exchange. The SBB exchange booths give acceptable exchange rates, unlike Travelex booths.
"Trafimage" maps and station plans are available for the larger stations and are very complete. They can be downloaded or zoomed in on-line.
plans.trafimage.ch/gen eve#?lang=en&layer=geneve_a ussenplan&x=499976&y=1 18524&r=0.19
and, this "shopping plan" map does not seem to show ATM's, but it does show the Tourist Info office at location # 100 in map section A8, which is just outside the station. You'll probably pass one of the ATM's there on your way to the Tourist Info office if you want to walk there.