How to say goodbye to my coach?

So my track/cross country coach has coached me since I was a freshmen (I will now be a senior this year) and has made a HUGE impact on my life. He has helped me become a stronger person and pushed me beyond what I even thought possible. He helped lead our team to a state championship and convinced me to run track which I then received all-state honors in because of him. Unfortunately, he has to move this year because of family issues and I can see this is really hurting him because he loves our team and we deeply depend on him each week. I know I'm going to have to say goodbye but I really don't know how! Should I write him a letter, speak to him in person about everything he has done for us, give him a gift?? We are planning to do something for him already with our team but I want to do something else personally since I'm the captain to show him how much he has helped me...any advice?