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