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