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