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