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