Those who don't share the same skill set need more than just a configuration diff from a switch to get the idea. They need pictures and concrete evidence.
This is why even the most CLI-centric admin should be using network monitoring and mapping tools like Nagios and trending tools like Cacti. You can sit just about anyone down in front of the Web interface for a reasonably large Cacti installation and hammer home the key points of what IT does. Most people are blown away that IT monitors every aspect of the infrastructure from switch CPU usage to the airflow and ambient temperature in wiring closets and computer rooms. Network maps are slightly less impressive for some reason, perhaps because they're harder to digest, but a good Visio rendering of a network can't be beat.
It's a fact of life that IT lives in the shadows, only attracting notice when there's trouble afoot. It doesn't help that most businesses consider IT to be a cost center. So deal with it: Internal marketing is part of your job. Take the time to blow your own horn and let people know what you do and how important it is to the overall company, not just when you're proposing your budget, but when you reach milestones that provide value to the business. Make it an educational experience with some nice visuals and it won't seem like shameless self-promotion. After all, if you can't provide a cogent account of what you've done, nobody else is going to.
So tell me, what do you do?