。
She puts on a ladylike act.
Literal
She [topic-は] ladylike [attributive-な] pretense [object-を] do.
しとやか (淑やか) is a na-adjective for graceful, modest, well-mannered behavior — traditionally associated with feminine refinement and a certain quietness of demeanor. The word evokes old-fashioned Japanese feminine ideals: it's not pejorative on its own, but it does carry a particular cultural template of womanhood that has aged in step with shifting gender norms. Pairing しとやかなふりをする ('pretend to be しとやか') gives the sentence a hint of irony — she's putting on a performance of refinement that isn't her natural self. The ふり in ふりをする comes from the verb 振る ('shake, swing'); the noun 振り originally meant 'gesture, manner' before specializing into 'pretense, act.'