These three phrases roughly mean the same thing, but のための looks less formal and it does not usually form a set phrase. 向け sounds more formal, and 用 appears commonly in a serious technical set phrase.
For example, there is nothing wrong if you say 管理職のための雇用契約書があれば送ってください in a business email. But if you are instructed to download it from an internal webpage, the link would probably say "管理職用雇用契約書", "雇用契約書(管理職用)", etc., because these would look more like one phrase as a whole.
On the other hand, a book like this does not usually use 用 because the title is intended to look more like a friendly, ordinary sentence that contains both kana and kanji. Using 用 would look too stiff.