SFML's license only comes into effect when you distribute SFML's source code.
The.libraries can.be used in anyway and don't require any credit. If you do want to give credit, which we highly appreciate, you can do so in anyway you want.
In the past I have for example seen people show the SFML logo when starting the game. Other ways I can think of is simply mention something like "Created with SFML" in the credit list somewhere.
But as I said, you're free to do whatever you like (text, logo, links, animation, etc.).