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