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