～の姿 / ～姿【～のすがた / ～すがた】

姿 is someone's figure as another person sees it: how they look, or the sight of them doing something. A verb in the plain form goes straight in front of it, and a person or an animal takes の.

• × 子供たちが遊ぶの姿 → 子供たちが遊ぶ姿

What 姿 adds

A sentence with 姿 is about something seen, and it usually carries the watcher's feeling – admiration, nostalgia, worry. It pairs with みる見る, みせる見せる and みかける見かける, or with a reaction such as かんどう感動する. のをみる見る reports the same event as a plain fact.

Clothing: スーツ姿

An item of clothing joins 姿 as one word, with no の: すうつすがたスーツ姿, きものすがた着物姿, せいふく制服すがた姿. The person wearing it comes first, with の.

• × 着物の姿の彼女 → 着物姿の彼女

姿を見せる and 姿を消す

With みせる見せる and けす消す, 姿 stands for the person: "show up", "disappear". げんき元気なすがたをみせる姿を見せる is a set phrase for letting people see you are well. Both are common in news and narration.