The traditional image of a New England puritan is that they were dressed in black, with a steeple hat and lots of buckles. None of these is historically accurate; this is a 19th-century idea of how a puritan would have looked, with the buckles representing a stereotype of quaintness. Actually they normally dressed as colourfully and variably as everyone else.
Black suits were for Sunday best, because black dye was expensive and faded fast. If you were having your portrait painted, you wore your best clothes – which is why portraits tend to show them in black. (They are also sometimes depicted as armed with a blunderbuss, but this is another invention: it’s a crowd-control weapon, not a hunting piece.)
“The objection to Puritans is not that they try to make us think as they do, but that they try to make us do as they think.” – H.L. Mencken
Also, Puritans aren’t the same as pilgrims. The Mayflower Pilgrims were a mixture of utopians and fortune hunters, and welcomed dissent. The Puritans, on the other hand, came to America not to find religious freedom so much as to take refuge from it: their party had lost power in England and they wanted to go somewhere that remained free of the taint of religious tolerance. Puritans were not fleeing religious persecution so much as trying to establish an environment in which they could persecute others.
They were active suppressors of religious freedom: for example, a woman named Mary Dyer was hanged in Boston in 1660 for being a Quaker. Those legal measures to promote religious tolerance which did exist were promulgated from England and imposed on the colonies against their wishes.