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