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