Wojciech Sznapka has shares his technique for creating colorized exports of Behat tests for use in PDF files:

Behat scenarios are one of the best ways to describe system. UML Use Cases or tons of pages in SRS documents are fine, but hard to understand from the begining, and even harder to maintain in the future. Behat eases this process and also gives opportunity to automate requirements verification. To write Behat scenarios you need a text editor. I’ve picked my favourite – Vim, which highlights *.feature files syntax. But business people mostly don’t use Vim, so I need to figure a way, to expose scenarios in easy and pleasant way.

His solution involves setting up some printing options in vim to export the tests as a Postscript file, setting the "colorscheme" to the default setting so the colors will be retained. The result is exported (via the "hardcopy" command) and can be converted into a PDF (with a result like this).