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)(27,33)(28,36)(29,35)(30,31)(32,37)(34,39)(38,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(11,17)(15,21)(18,23)(22,24)(25,27,30,35)(26,29,31,33)(28,34,37,38)(32,39,36,40)(2,5)(6,8)(10,14)(15,21)(16,19)(22,24)(26,31)(28,37)(29,33)(34,38) involution — undirected(3,7)(6,8)(9,10)(11,15)(12,16)(13,14)(17,21)(18,22)(19,20)(23,24)(25,28)(26,32)(27,34)(29,39)(30,37)(31,36)(33,40)(35,38) involution — undirected(1,3)(2,6)(4,7)(5,8)(9,11)(10,15)(12,18)(13,17)(14,21)(16,22)(19,24)(20,23)(25,27)(26,33)(28,38)(29,31)(30,35)(32,39)(34,37)(36,40) involution — undirected(1,2)(3,6)(4,5)(7,8)(9,12)(10,16)(11,18)(13,20)(14,19)(15,22)(17,23)(21,24)(25,29,30,33)(26,27,31,35)(28,39,37,40)(32,34,36,38)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.