there are visuals on some of the old sexing threads, but this I can tell you:
in a female there tends to be a little "belly" right before the vent, and there is a more abrupt tapering between body and tail at the vent, whereas in males the tapering is more gradual. some males have a slight bulge after the vent where they keep their hemipenes, but with some the transition is so gradual that it's hard to find the vent without turning the snake over and looking closely, whereas in a female, often the change at the vent is so obvious that one can tell where it is even in profile