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