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