Snapchat follows a strict privacy policy that doesn't allow it to show mutual connections. That being said, there is a way you can get a look at your friends and an approximate number of mutual friends you both have. To see this, simply open your Snapchat app (make sure you are logged in with your active account). Now click on the +(user icon) on the top right corner of the app. Upon clicking, you'll see that a list of all your connections comes up. In the search bar, you can type your connection's name. When you hit search, the connection's name comes up along with an approximate number of mutual they have with you, e.g. 10+ mutual friends.