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