One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,6)(4,5)(7,8)(9,10,14,16,12,17,13,18)(11,19,22,24,20,15,21,23)(2,5)(6,8)(9,11)(10,15)(12,20)(13,21)(14,22)(16,23)(17,19)(18,24)(25,26,29,32)(27,33,34,40)(28,36,38,31)(30,37,39,35)(10,16)(13,14)(15,23)(17,18)(19,24)(21,22)(25,27,29,34)(26,30,32,39)(28,37,38,35)(31,40,36,33)(1,3,4,7)(2,6,5,8)(11,20)(15,19)(21,22)(23,24)(27,34)(30,39)(33,40)(35,37)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.