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