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