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)(11,16)(12,18)(13,21)(14,19)(15,20)(17,22)(23,24)(26,32)(28,37)(33,34)(35,39)(1,3,4,7)(2,5,6,8)(9,11,15,23)(10,16,20,24)(12,14,22,21)(13,18,19,17)(25,26,31,32)(27,33,30,34)(28,38,37,29)(35,40,39,36)(1,2)(3,5)(4,6)(7,8)(9,12)(10,17)(11,21)(13,24)(14,23)(15,22)(16,19)(18,20)(25,27,31,30)(26,33,32,34)(28,35,37,39)(29,36,38,40)(1,3)(2,5)(4,7)(6,8)(9,12)(10,18)(11,14)(13,24)(15,22)(16,19)(17,20)(21,23)(25,28)(26,29)(27,35)(30,39)(31,37)(32,38)(33,36)(34,40) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,13)(10,14)(11,18)(12,24)(15,19)(16,22)(17,23)(20,21)(25,29)(26,28)(27,36)(30,40)(31,38)(32,37)(33,35)(34,39) involution — undirected(9,14)(10,19)(11,22)(12,23)(13,20)(15,21)(16,17)(18,24)(25,30,31,27)(26,34,32,33)(28,35,37,39)(29,36,38,40)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.