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