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