It's just html
I know html inside and out so it's pretty simple. If you're not knowledgeable in that language, you'll need to learn the basics. Using FP or something to generate your code will result in a bloated mess.
Edited to add: changing the home.tpl page will do most everything. You can stick the links directly in there instead of calling categories.tpl or head.tpl or other pages. Just my preference, but that's way I like to do it.
Here are 3 more in progress - they're a mess as I'm right in the middle of settling on layout and such...
http://www.magichandsworkshop.com/store/customer
(in this one I've added a JS mouseover to the links...)
http://www.freshhandmadesoaps.co.uk/store/customer
(the category links run side to side across the top rather than down the sides)
http://www.webgyrl.net/clients/fp/store/customer/
(categories down both sides)
If you know your basic html, it's pretty easy. HTH