The word driver is more general - anybody who drives a vehicle is a driver. You are a driver when you are driving your car. Some people work as bus drivers and taxi drivers (the drivers of trains are usually called conductors).
A chauffeur is a person who is employed to drive a car for a private individual. Rich people and celebrities often have chauffeurs so that they do not have to take public transportation, or drive themselves.
All chauffeurs are also drivers; not all drivers are chauffeurs.
Every success must be celebrated with the team, we may just have a small get together, and the leader of the team must talk about the success story and also share the name of the key contributors. This may be followed by a token of appreciation in terms of small gifts or certificates signed by the leader. Celebration is a vital part of project management.