Quoting "Jon Harrop" <jon@ffconsultancy.com>:

> On Monday 30 March 2009 23:38:45 Ed Keith wrote:
>> I do wish I had better tools for visualizing FP designs. I use
>> Nassi-Schneiderman diagram for procedural designs and UML of OO designs.
>
> That's an interesting idea. Someone must have worked on this?
[...]

In the book "Haskell: The Craft of Functional Programming"
at some pages are graphical notations, at least explanatory,
for some things.


A paper which you also might find interesting:

"To Dissect a Mockingbird:
A Graphical Notation for the Lambda Calculus with Animated Reduction"

   http://users.bigpond.net.au/d.keenan/Lambda/index.htm


Ciao,
    Oliver