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