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