As you can tell from her un-Japanese beautiful features, Yuna is actually not fully Japanese. She's a quarter — her grandmother is Western.
Literal
Japanese-person-departing this beautiful features [from-からも] understandable [like-ように], Yuna [topic-は] actually pure Japanese not-is. Westerner [object-を] grandmother [to-に] having, quarter was-[casual-たりする].
日本人離れした ('departing from Japanese norms' = 'un-Japanese') is a compound modifier. 相貌 (そうぼう, 'facial features, countenance') is literary. 生粋の日本人じゃない ('not a pure-bred Japanese person') uses 生粋 ('pure, genuine'). クォーター ('quarter,' i.e., one-quarter non-Japanese) is the standard Japanese term for someone who is one-quarter foreign. だったりする softens with 'it turns out' casualness. The sentence reflects Japanese discourse about mixed heritage.