The first thing to catch my eye was a big sofa. Upholstered in leather of a subdued color, with a roomy seat and backrest.
Literal
First eye [into-に] came-jumping-[relative-てきた] [nominalizer-の] [topic-は], big [attr-な] sofa is. Subdued color [gen-の] leather-covered [and-で], seat-surface [also-も] backrest [also-も] roomy is.
目に飛び込む ('to jump into one's eye') is a fixed idiom for 'to catch one's eye / to be the first thing one notices.' The past ~てきた captures the completed moment of noticing. 革張り ('leather-covered / leather-upholstered') uses 張る ('to stretch, to cover') in noun form. 渋い ('subdued, refined, tasteful') describes muted colors or mature aesthetic taste — a distinctively Japanese aesthetic vocabulary. ゆったりしている ('is roomy, spacious') from ゆったり, a mimetic for relaxed spaciousness. Scene-setting prose with refined vocabulary.