Fresco from 1st Century Pompeii
Women in 1st century Rome had a lot more freedom in their clothing then men did. They could wear a variety of styles and colors (though darker and more vivid colors were limited to the upper class, simply because they were more expensive - you are safe with any faded pastel, brown, beige, white or grey).
A simple Roman women's outfit
Below you can find info on how to make several common roman women's dresses:
How to Make Roman Costumes for Women
Colors Available to Commoners and the Rich
More Info on Women's Dress (if you're interested)
A Pinterest page Full of Ancient Jewelry (not mine)
Just search the page for "Roman" - there's a lot
Two Ways to Wear a Peplos, one with a belt underneath,
one with a belt above.
A woman with a tunica, stola, and palla (wrapped around her).
Detail on women's sleeve...one way they wore them.
Pictures courtesy of VRoma and Wikipedia Commons