Actually there is recent evidence that they might be from somewhere alot closer to home.
Probes have picked up a broadband radio jamming signals from Saturn. When filtered using fm modulation, it has a melody that is somewhat similar to the classical music of the 1600's. It is possible that maybe the Russians sent a probe that now orbits in one of Saturn's rings to prove they were there before the Americans since the music does seem earthlike and deliberate.
This seems more likely. We know enough to know that travel above the speed of light is not so easy and that hitting debris in a spaceship would be a issue. Maybe at best travel at 1/4 the speed of light is possible within reason. So travel from Saturn would be within reason.
We don't know what chemicals other life would be based on, ours is based on carbon, Saturn has vast dense compressed gas oceans, the gas is so dense it is liquid like, we don't know whats in that ocean.
If you watch star trek, humans would defiantly look like the "Klingons" on the show. On the show current humans are portrayed as the "Klingons" and the star trek crew as future humans that they hope we advance to.
Think about this, if you were looking at humans on earth, what would you observe? Yes we would look like a bunch of "Klingons" fighting amongst ourselves. The show's portrayal is actually pretty accurate.
If there are aliens that visit. They might not try and contact us. If you met a people like the "Klingons" you might fear them and leave them alone. If a air force shot them out of the sky somewhere or made them crash with some sort of magnetic coil or radio signal, that is not much a welcoming mat is it? If they watched us for the last 100 years, in the last 100 years people on earth have had quite the track record. You have to ask the question. Would they even want to talk to us?