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