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