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