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