Your coach is right and wrong.
If your goal is bodybuilding, you want to train with a fast pace to keep the blood in the muscle and your heart rate up. This will give you the best pump and best fat burning effect during your workout.
For small muscle groups I like 30-60 seconds rest between sets.
When you are training big compound lifts like squats, deadlifts - I like 60-90 seconds between sets.
Use as much rest as you need between sets but no more. I always tell my clients to train with a go go go mentality. Train like you are late for work.