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