。
She catches colds so easily, you know.
Literal
She [topic-は] easily cold [object-を] catches [explanatory-の][feminine-よ].
風邪を引く ('catch a cold' — literally 'pull a cold') is a fixed idiom; the verb 引く ('pull') here is the same one used for getting illnesses, drawing attention, or pulling a chair. のよ is a sentence-final cluster mostly heard in feminine speech: の (the explanatory particle) + よ (assertion) — together giving an emphasized, slightly affectionate explanatory tone, as if confiding 'you should know'. Compare male speech, which would more often use のだ, んだ, or んだよ. すぐに here means 'easily / readily' (habitual sense), not 'right away'.