Conal Elliott, Haskeller of FRP fame, was recently working for a company where he was developing a compiler of functional programming into categorical semantics which is actually quite neatly similar to the layout of a circuit. The company went under, unfortunately, so I'm not sure of the status of his research, but some remarks are available on his blog [0] [1] [2].
Further, there is a notion of a Generalized Arrow [3] which is a useful, advanced functional programming technique which is quite nice for implementing FRP. These are somewhat obviously "wiring diagrams" but are shown to be in correspondence with a more normal "lambda calculus"-like syntax.
[0] http://conal.net/blog/posts/haskell-to-hardware-via-cccs
[1] http://conal.net/blog/posts/overloading-lambda
[2] http://conal.net/blog/posts/optimizing-cccs
[3] http://www.megacz.com/berkeley/garrows/