Yeah, the FSA 57 is consistent with the one used in the Rocky mountain instinct (a 57E), which is what this frame appears to be a close copy of.
A quick google shows these 3 headsets:
https://shop.fullspeedahead.com/en/no-57e-3425If you have a tapered steerer on your fork, you can't use the 57E-1. Either of the other two should work, depending on what stack height you want. I personally go for the lowest stack height usually, as it give more flexibility to lower the stem further.
To be sure, you could measure your frame's headtube. The pdf on that page has headset measurements for those FSA headsets. The cup heights, including the lip, are 12mm top and 11.5mm bottom. the lips are 2mm, so the headsets will go 10/9.5mm into your headtube. However, if you look at the diagram, that 10/9.5 includes the taper on the headset, which looks to be about 3mm for the top headset cup, and about 1mm for the lower headset cup (if you compare the thickness of taper with other measurements in the diagram). Therefore, to fit this headset in your frame, you need about 7mm (10minus3) of depth in the top headtube before it tapers in, and about 8.5mm for the bottom Does your frame have these measurements (or greater)? The headset could probably still work with slightly less, but it wouldn't press completely all the way in, so it wouldn't be ideal.