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