Some things I did, I used to have a real problem:
Shower or at least ho-shower before riding. Since smell is usually from bacteria on your body. Washing it off right before helps.

Wear natural fabrics for your base layer. If you can afford merino wool jerseys I find those to be the best. But even on sale at sierra trading post they are about $50 a pop so I only have two. But two last me the week.

Slow down, or at least towards the end. Don't overdress. etc.

Maybe the outer layer also needs to be looked at if it's causing you to sweat. I prefer the kind of outer later that is "breathable" and you have wash in woolite and re-apply waterproofing every few months. I find those better than more waterproof solutions where i just sweat a ton in.

edit: funny someone mentioned diet. Since my 95% vegetarian (she eats meat once a month) g.f. moved in with me I find I smell much better. I used to eat low carb (dieting) but now I eat more rounded and less meat sources of protein. (I still eat meat almost every day) but I just smell better. (well ok the sweat doesn't smell as bad, all the extra fiber causes other smells ... )