There's no single universally agreed upon visual location. It could be on either side of the car or even slightly forward. The best approach is to:
1. Consult a repair manual specific to your 1994 Pontiac Sunbird. This is the most reliable method. A Haynes or Chilton manual will show diagrams and instructions.
2. Use an online parts diagram. Websites that sell auto parts (like AutoZone, Advance Auto Parts, etc.) often have diagrams you can view by entering your vehicle's year, make, and model. Look for diagrams showing the fuel system.
Trying to locate it visually without a guide is difficult and potentially dangerous due to the presence of pressurized fuel. Always prioritize safety and consult the proper resources before attempting any fuel system work.