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