。
She gave him a tie that matched his taste.
Literal
She [topic-は] him [to-に] taste [to-に] fit-past necktie [object-を] gifted.
好みに合った is a relative clause modifying ネクタイ — '(a tie) that fit (his) taste,' with 彼の implied from context rather than stated. The recipient takes に for the gifting; the standard being matched against also takes に in the Xに合う pattern: 好みに合う ('match someone's taste'). プレゼントする ('to gift, give') is a する-verb made from the loanword プレゼント.