The Clicky GUI comes with Click, in the apps/clicky directory. This silent screencast shows what it's about (click "Go" to begin).
(If Flash is installed JavaScript is activated, you can watch a video inside this web page.)
Clicky can show Click configurations as text (with syntax highlighting) or diagrams, and can read and write handlers in live configurations. It can also generate output diagrams in PDF format.
To build the Clicky GUI you will need recent packages for autoconf, automake, and GTK+. On Ubuntu "libgtk2.0-dev" should suffice. First, build and install Click into some prefix, PREFIX. Then:
cd CLICKDIR/apps/clicky
autoreconf -i
./configure --prefix=PREFIX
make install
See clicky-css for information on the CSS-like language used to style Clicky diagrams.