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