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