"Candyland" is a very popular board game in the United States. It is close to a cultural universal be cause it is often the first board game that children are able to play. It is a game of pure chance, and no reading or writing is required, only the ability to count and understand very simple rules. It involves progress along a path of brightly colored squares, past brightly colored pictures of fanciful candy buildings and landscapes. The socks must be in bright primary colors, the kind that young children like--no doubt with some sophisticated and subtle difference that makes them worth designer prices. Following Ben's suggestion, I don't really like the assortment of images Google is finding me, so let me suggest this one: http://www.rarityguide.com/museum/images/card_and_board_games/candy_land__1955_/candy_land_mb_game_board_closeup3.JPG

You would be looking at bubble-gum, sweet (candy) and birthday cake colours such as icing pink, yellow and green, etc. Candyland is a board game. Look it up for the colours under Google images. What Americans call candies the British call sweets.

Generally, the term "candyland" would be a reference to a utopian world, a kind of dream-like, idealistic world. I cannot be sure of its use regarding fashion and socks.