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