Trav changed color when grouted?

We had a travertine back splash installed a few days ago. Its a pale tan. But when the installer put the grout on it turned the Stone (http://g603.net) into a dark tan. The installer keeps telling me its a "grout haze" and (http://maplered.com) to keep wiping it down. It's been a few days and (http://maplered.com) the color is still much darker than it was before he did the grout. I have some left over Tiles (http://www.g682.net) to compare it to so I know I'm not going crazy. What can I do to get the color back? Also, the installer made some pencil marks on the Stone (http://g603.net) and (http://maplered.com) I can't get those to come off? Any suggestions would be very much appreciated.