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