Generally, two individuals have to "look at each other" in order to "exchange looks." "To look at each other" is a neutral statement of act. When A looks at B, and B looks at B, they are looking at each other (お互いを見る） "To exchange looks" goes a step further. In addition to physically looking at each other, when A and B exchange looks, it is implied that they are communicating some common understanding/knowledge/agreement by the looks on their face without expressing their thoughts out loud. For example, A and B both know that C is a very boastful person. When C predictably starts to tell tall tales about how smart he is, A and B may "exchange (knowing) looks," acknowledging, for example, their common dislike of C through their facial expressions, without saying anything verbally. I hope this was helpful!

Technically they are the same, but there are subtle differences that can be given with "exchanging looks". People "looking at each other" is factual and is not dependent on time. Exchanging looks typically is brief. For example imagine Two young people shyly exchanging looks from across the room. They are not staring. It is brief. Compare that to two gunfighters that intently looked at one another. That later example is longer.