The most description we are given of the Devil in this excellent short story is when we are first introduced to him - when Tom discovers a cloven skull and kicks it to shake the dirt from it. Consider how we are introduced to the Devil, or "Old Scratch" as Tom calls him:
Tom lifted up his eyes, and beheld a great black man seated directly opposite him, on the stump of a tree. He was exceedingly surprised, having neither heard nor seen anyone approach; and he was still more perplexed on observing, as well as the gathering gloom would permit, that the stranger was neither Negro nor Indian. It is true he was dressed in a rude half-Indian garb, and had a red belt or sash swathed round his body; but his face was neither black nor copper colour, but swarthy and dingy, and begrimed with soot, as if he had been accustomed to toil among fires and forges. He had a shock of black hair, that stood out from his head in all directions, and bore an axe on his shoulder.
What is important to note in this description is that the Devil is described in such a way that does not link him to any race - note how he is described as being "dark" but not of any recognisable race. He wears some Native American clothing but is not Native American. In addition, the description paints him to be a mysterious and enigmatic figure - note how he appears without having been heard, and also how his face is covered with soot as if he works round a fire, even though there is no fire in the swamp.
These descriptions certainly promote the Devil's Everyman qualities, as we see the figure of the Devil as not linked to any geographical location or area or even time, and thus is free to work in all places and periods.