Santa Claus evolved from a group of magical figures associated with the giving of presents at this time of year. Three of these were St. Nicholas (Dutch, I believe); Belsnickle, a dwarf like figure who wore furs and had a beard and the invisible Christkindlein (Christ child). When different nationalities went to America, their different traditions began to mingle, just like the people. Christkindlein's name became Kriss Kringle and Belsnickle grew into a full sized man.
The colours associated with Santa were originally quite varied and included greens, reds and purples, but they too evolved and by the 1880's, Christmas cards were being given out in America showing a full sized man with a beard, dressed in clothes of red with fur trim.
This image became even more popular when Coca Cola used it to promote their products in the 1930's.
Hope this helps, but the true story is even more complicated because I haven't gone into all the different traditions from old Europe that went into the melting pot that gave us Santa Claus, or Father Christmas. There are just so many.