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