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