You are describing a leucistic (not alibino) coloring of the swans known as the Polish Mute swans which is very common. Royal Mute swans have taupe grey colored cygnets which have black feet. The Polish Mute swan cygnets are white colored with light pinkish feet.

An albino means absence of or no coloration. Years ago, someone in Poland or the surrounding area, tried to inbreed an albino mute swan. This white swan, at one time thought to be a subspecies was known as "cygnus immutabalis", the white or unchanging swan. However, taxonomists agreed that this was not a species or subspecies, just a color variation known as leucistic.

Because what you describe is a coloration, the Mute Swans are still known as Mute Swans taxonomically, but swan keepers refer to them as either Polish or Royal Mute Swans depending on the coloration of their cygnets as well as the adult coloration which has a paler beak and foot coloration. We hope this information helps. The Regal Swan