One of a kind can be meant as “unique”. If I say that your hairstyle is one of a kind, it means that I will never find anymore people who have the hairstyle like you have. You are the only one who has such hairstyle. Anyway, I am not so sure if you are really the only one, but I am really interested to say that so you will feel flattered. I also can say a fact that I have never found someone with such a hairstyle. So, in this case, “one of a kind”, in general, just to say that one thing or one person is unique as far as the speaker knows.
As usual, please contribute here by giving us your voices in the comment box below.