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