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