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