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