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