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