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