Back when we first created the guild on Horde, our Tabard was black with a white edge and logo, and was the symbol that resembled the Horde logo. Not very long after, another guild set theirs as the exact same. They were much larger at the time, and I wanted our Tabard to be more original, so off to the drawing board I went. Considering there are a set amount of logos, border styles, and colors to choose from, one could never truly have a one of a kind Tabard.
I changed the logo to the one that appealed most to me, and fit the guild and what I wanted it to represent. That choice was what is known as a Fu (or Foo) Dog, Fu Lion, Guardian Lion... etc etc.
So how the heck does this 'represent' the Guild? Well, in the past we were staunch defenders when our cities were under attack, and now, as Alliance, the fact that it is an interpretation of a Lion is even better. Plus, it just looks cool. The colors were just ones I thought went nicely together and gave it an interesting look. The Horde guild Tabard is the same, but was changed back to black and white.