。
She has graduated from college.
Literal
She [topic-は] college [object-を] is-in-the-state-of-having-left.
出ている here is the resultative ~ている of 出る ('leave, exit') — 'is in the state of having left college,' i.e. 'has graduated.' Without the ~ている, 大学を出る would be present/future; the ~ている locates the result in the present. Same shape applies to other change-of-state verbs: 結婚している ('is married,' from 結婚する 'get married'), 持っている ('has,' from 持つ 'pick up').