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