Keeping a beard is a Sunnah act in Islam. Keeping a long beard is considered a symbol of celibacy for them.
There are varying opinions in Islam about keeping a beard, whether keeping a beard makes you distinct from infidels or whether keeping a beard is a sign of following the orders of the Prophet Muhammad.
Most Muslims dye their beards red or orange. It is said that the natural dyeing method was also used by Prophet Muhammad. While there is no such religious belief in Islam.
Dyeing the beard can be everyone's personal decision. There are no rules related to this in Islam. People dye their hair and beard for aesthetic reasons.
Islam encourages the wearing of a beard, but there are no specific guidelines regarding its length and colour.
In films, TV serials, most of the Muslim characters are shown with red beards, due to which the common perception is that all Muslims look like this, which is completely wrong.