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