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