Try to look at it from your cat's POV for a second. You're locked in this tiny room. You don't know that it's temporary. You don't know why you're in there, but you do know there's a big house to explore right outside the door. You're alone and extremely bored.

Do you just sit there doing nothing, or complain until someone comes along and gives you attention? I'm guessing the latter. You can try a few different things - I would use Feliway spray in the entire room, including on the door, and I would also use a Feliway diffuser. You might try introducing a calming supplement into her diet - there are many on the market.

Make sure she has everything she needs in there - plenty of fresh water, food, a litter box, and LOTS of things to enrich her. When I have to keep a cat in a room, I make sure they have a scratching post, a nice big cozy bed to hide in, a box or a cube to play in, dozens of toys, access to a window to look out of, a radio to keep them company, etc. If they walk well on a leash, I'll take them for a decent walk every day.

Please don't punish her with a squirt bottle or be mad at her. She's just doing what comes naturally.