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