Air carrier First Officer reported a possible taxiway incursion occurred at JFK due to the ramp exit area being unclearly charted and causing confusion about the location of the taxiways.

Narrative

After pushback from Gate XX; JFK Ramp gave us instructions to use minimum thrust; exit Sierra and contact Kennedy Ground. This matched our threat-forward briefing of getting a taxi clearance while still parallel to the terminal to avoid jet blast to the terminal.I called Ground; stating Sierra as the location. We were 90 degrees to Sierra parallel to the terminal. Ground cleared us; Runway 31L; taxi left Bravo. Hold short of Kilo." After readback; I looked at my Airport Moving Map (AMM) to locate Kilo. We had briefed an intersection departure from KE; but where was Kilo in that area? When I looked up; the CA had made our right turn onto Sierra Alpha. He had made the gentle half-right turn onto SA instead of following S perpendicular way from the ramp as I had expected. I told the CA we were on SA not S. Taxiway S was across an island to our right now. The taxiway location and direction signs were clear. There were no other aircraft in our quarter of the airport. The CA indicated we were going to turn left onto Bravo following Ground's instructions. We made the turn onto Bravo and changed our focus to verifying the performance for Runway 31L.Was that Ground's intention? I had identified our position as Taxiway S and we had used SA to turn left onto Bravo. The CA followed the instructions "taxi left Bravo" using a taxiway that made sense leading away from the ramp. I am submitting this report because I think the charting is unclear and could lead to pilot deviations if Ground intends to send aircraft along Sierra perpendicular to Bravo.Cause: When I looked at the AMM closely; I noticed that the taxiway centerline we used is labeled "S;" then later "SA." Conversely; the park gates chart shows SA and S as very distinct; parallel taxiways. The taxiway centerline we took is not shown on the 10-9 chart. SA is the easiest turn out of the ramp while using minimum thrust.I think this ramp exit area is poorly charted and could be updated or marked as hotspot. We had identified 2 taxi threats during our brief; jet blast and the KE intersection performance planning. The CA had briefed the route but only generally described S as the exit point to turn left on Bravo to parallel 31L. I assumed this would be a series of 90-degree turns. I misused a barrier to error when I looked away from our turn to reference our hold point Kilo on my chart. Our geometry to avoid jet blast set us up with an initial turn.How to mitigate risk: Removing the "S" label from SA could make the AMM easier to use at-a-glance. The area could be marked as a hotspot because of the mix of a diagonal taxiway centerline across island divided taxiways. As always; crews should use the charts to brief the expected routes. We did. Crews should also announce intentions and stay heads up for turns."