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