If you zoomed out of the universe what would it look like?

If one defines the universe as all the mater and energy that there is, then there would be no way to get "past" it, but even in the hypothetical situation that you were somehow able to be outside the bounds of all matter and energy (aside from yourself and whatever vessel you were in), you would see nothing -- complete blackness, because the matter and energy that make up the universe that you are beyond would include light. Light travels at a finite speed -- incredibly fast, but a finite speed. When an astronomer describes a star 15,000 light years away, that means the light from that star is 15,000 years old or, in other words, it has taken the light from that star 15,000 years to reach you.

The universe, as we know it, was created (according to most theorists) in an event called the big bang about 13.7 billion years ago. Light began to emit at that point, so the visible universe would have a radius of 13.7 billion light-years (or a diameter of 27.4 billion light-years). At the extreme edge of this radius, if one could somehow instantaneously get there, one might see the 'flash' of the big bang explosion that created the universe. Beyond that radius, one would be too far away to see the light from the very birth of the universe and there would only be a complete black void in every direction. No light from stars, not even cosmic radiation, complete nothingness.

If you'd like an idea of how various things compare in size to the universe, you can check out the related link. It's a little misleading in some ways (for one thing, it presents "strings" and "preons" as if they actually existed... the jury is very definitely still out on that), but it's basically correct about relative sizes. Keep in mind that it's a logarithmic scale, not a linear one!