This is an unusual case. Usually when a book goes from hardback to paperback, it gets a new cover. In this case, though, the book keeps almost the same cover, but gets a new title--presumably Penguin were told that the original, 'Whore'-containing title was putting people (women?) off. (UPDATE: Author Neil Ansell explains that "I met the author when we appeared at the same literary festival, and she explained that the reason for the name change was because the chain WH Smith was refusing to stock the book with that title.")
In either case, the cover, drawn by Max Schindler, is a nice attempt at mimicking the illustrated boards of books from the era of the novel's setting, 1887.