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