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