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