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