One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(10,14)(11,18)(12,15)(16,23)(17,21)(19,22)(25,26,29,32)(27,33,34,40)(28,36,37,31)(30,38,39,35)(2,5)(6,8)(9,10,15,21,13,17,12,14)(11,16,22,24,19,23,18,20)(27,34)(30,39)(33,40)(35,38)(11,19)(16,23)(18,22)(20,24)(25,27,28,35,29,34,37,38)(26,30,31,33,32,39,36,40)(1,3,4,7)(2,6,5,8)(9,11,12,18,13,19,15,22)(10,16,14,20,17,23,21,24)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.