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