I had a double repair when I was 18, and the right side done with more modern methods (the mesh deal) about 10 years later, so I've been there twice. I really can't imagine that cycling would be a major issue as long as you don't push it hard on your rides. Stay in the saddle and take it easy, you should be OK.
But ask your doctor, he's the expert and knows the severity of your hernia. They are often over cautious, but that's better than a strangulated hernia.
I'm now working on a belly-button hernia myself. From what Mom says, the doc predicted it at birth, and that was in 1967. Now I'm in a weight-loss mode to satisfy the current doc before he decides to fix it.
"It hurts so good..."