Rendering
The hexagon would normally have been deliberately painted on the model if this was a typical rendering engine. Most such 3D systems will "paint" or "wrap" a prepared texture map around the spherical wireframe.
News releases on the hexagon feature state that it was discovered by Voyager 1 and 2, so it would be common knowledge to anyone interested in this.
On the other hand, it is common (at least in my work on spheres) to get geometric artifacts like this at the polar areas of spherical wireframes due to "wrapping" problems. Which would mean that either the renderer hit on this by accident, or that the real Saturn is actually a rendering... ;)