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