I don't see the mag safety on that drawing. The part looks like a plunger going into the back of the trigger (#033) and there is a very small pin going through the trigger along with a spring inside the whole assembly. You have to take the trigger out to take the mag safety out.
YOu can identify the right part by taking the slide off the gun, sticking a finger down inside the mag well and pushing forward on a square but flat part. This makes part # 35 swivel on the right side of the frame. If the mag is out with the safety installed, #35 will not engage part # 29 on the slide to fire the gun. If the mag safety is out, #35 has a spring sitting on top that holds it in its proper position to always engage #29.
In someone else's post they refer to part #39, but I am pretty sure that is the pin/spring at the front of the slide safety. As I said, I don't see a hole shown in the drawing of the trigger for the pin that holds the mag safety in place.
Hope this helps.