As you've already heard, actress Daisy Ridley is rumored to be playing Han Solo and Princess Leia's daughter in J.J. Abrams' Star Wars: Episode VII. Thanks to Jason Ward from Making Star Wars, we have a detailed description of the character along with some sketches showing us what the character might look like.
The concept designs you see here aren't actually from the film production. These were drawn by Ward who has seen the official concept design of the character, and he provided the following description:
"I had trouble with the loose free-flowing scarf, so I didn’t depict it. She has a ton of detail and gadgets on the costume, so please forgive me for any ambiguities. The pants reminded me of Boba Fett’s pants (they’re not). The knee pads, chest and scarf are a dark blue. The pants are grey. Her arms are a white 'bone' looking padding, tied off with brown straps. My sketch looks like she has a hat brim but that is supposed to be a transparent visor. It’s like a solid piece of glass or plastic and you can see her eyes through it. The stances below are nearly identical to the art I was shown.
"I believe when we are introduced to the character, she has all the gear on. When she returns from finding what she finds, she is dressed in the 'gear off' costume. I also have heard the concept art depicted are the costumes used in the film, but they’re a little less complex and busy in reality. It sounds like they needed to make them more practical for filming and movement, but that’s just a guess."
The outfit looks like something we'd see from the Star Wars universe. CBM points out that it looks like a mix of something we'd see someone wearing on Cloud City in Empire Strikes Back, and the gear worn by the rebels on Endor in Return Of The Jedi.
I just want to note, there's no confirmation that any of this is accurate, but the guy did offer a lot of detailed info so I'll give him the benefit of the doubt.