The Galaxy note 5 is available in four different colors, Gold, Black, White, and Silver and if you live in South Korea you can also get it in Pink Gold. All this to say that there’s no official transparent options available. The pictures that have been released are of Reddit user Skarface08, who made his own back casing for his device, with fantastic results.
He didn’t create a new casing for the phone, he quite ingeniously removed the color film fixed behind his own Galaxy Note 5’s glass. Getting the back out of it might seem a hard task, and possibly would leave some marks, but it’s actually not that difficult. All you need is a heat gun, a suction cup and a razor blade. Since the case is only attached to the back, what he did was heat the edges of the case and pull them using the suction cup, releasing the back. Then, using the razor blade, he took out the colorful film, after that it was just to stick it in the back with adhesive to hold it firmly.
Keep in mind, if you try to do this, to not focus the heat source in one place for too long, ideally it should be in constant movement to spread the heat and not damage any of the sensitive internal components. The front end doesn’t produce the same effect, unfortunately.