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