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