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