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