The one you're looking at should be just fine. You'll need the pinout information so you can wire your 12V and your switch.
If you're referring to the orange thingy, that is not a switch, it's a locking tab that lock the PSU into the server backplane, and is not used in our setups. These power supplies don't usually have a physical power switch. They are ATX power supplies and they're powered on by the main server power switch.
This is why you'll need the PSU pinout. The back of the PSU looks like this:

ON the left you have a bunch of control & signal pins. The 6 large connectors are the +12V and 12V return (3 + 3).
Once you know the pinout, you'll be looking for 2 pins, one called PS_ON, the other PS_Kill. Grounding these 2 pins will power non the PSU. So you'll have to first connect PS_ON & PS_Kill together, then run a wire to a switch. Run another wire from the PSU ground to the other connector on the switch. That should be your ON/OFF power switch.
Then you'll need to connect the PSU 12V output to your Solidoodle. Yous should first bridge the +12V connectors together then run a heavy duty wire from there to your Solidoodle power input. Do the same for the 12V return.
That's it. If you really want to get fancy, then you might want to buy a lighted switch, in which case, you should run 12V to the power switch LED as well.

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To print or, 3D print, that is the question...
SD3 printer w/too many mods, Printrbot Simple Maker Ed., FormLabs Form 1+
AnyCubic Photon, Shining 3D EinScan-S & Atlas 3D scanners...
...and too much time on my hands.