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