。
She's neatly dressed.
Literal
She [topic-は] neatly-done attire [object-を] is-doing.
服装をする/している ('to be dressed in [some way]') is a fixed pattern that treats the outfit as a state the person occupies, paralleling 顔をする ('have an X face/expression'). The past attributive さっぱりした modifies 服装: さっぱり is a versatile mimetic for 'refreshed, clean, neat, simple' — applied to looks, it implies a tidy, uncluttered, fresh appearance, free of fuss or excess. Quite different from elegant or fancy: someone in さっぱりした服装 is well-put-together but unshowy. Cultural register: dressing 'cleanly and simply' is a Japanese aesthetic ideal that also extends to food (さっぱりした味 = 'a clean, light flavor').