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