You cannot have a No Coloreds sign on your business. Where have you been for 50 years?
Federal Civil Rights Act of 1964, which prohibits discrimination by privately owned places of public accommodation on the basis of race, color, religion or national origin. Places of “public accommodation” include hotels, restaurants, theaters, banks, health clubs and stores. Nonprofit organizations such as churches are generally exempt from the law.
That of course flies in the face of the 1st Amendment guarantee of freedom of association.