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