You might take a look at Ancestors of American Presidents. Many libraries have it, and the second edition is apparently still in print and available from American Ancestors for less than $40.
The book sources for the presidential family trees. There are charts with royal descents, relationship between the presents, some Mayflower descents, interesting ancestries of some First Ladies, and other interesting relationship. It is not exciting reading, but is the sort of book most genealogists would enjoy.
PS President Clinton’s Ancestry is there.