I used to worry about people seeing my diaper bulge under my sweat pants or jeans but now I realize that most people don't notice the diaper I'm wearing or if they do they haven't said anything.
I wear diapers 24/7 now because I love to wear diapers and no one has said anything to me about my diapers.
A onesie can help hold the diaper up in place and prevent the diaper from sagging and bulging out your jeans when it's wet and wearing a tight fitting undergarment could also help to compress the diaper and help hide the diaper bulge.
Another benefit to a onesie which is a shirt that snaps in the crotch is that it will hide the diaper from view should you bend over and your shirt rides up.