What does a 1957 US 1 dollar silver certificate look like?

The layout of the back is essentially identical to modern $1 bills.

The front is similar but with some obvious differences, such as the Words "Silver Certificate" and "In silver payable to the bearer on demand"; a blue seal and serial numbers; and the absence of a Federal Reserve seal.

Beyond that, an actual picture is much more instructive. While it's not Answers.com policy to say "use the internet", that's the best approach in this case. You can use any major search engine to look for "1957 1 dollar silver certificate images" or a similar phrase.