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