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)(25,26,30,28)(27,33,34,31)(29,36,37,32)(35,38,40,39)(6,8)(11,18)(14,17)(19,24)(22,23)(26,28)(27,34)(29,37)(38,39) involution — undirected(5,6)(7,8)(9,10)(11,14)(12,15)(13,16)(17,18)(19,22)(20,21)(23,24)(25,27,30,34)(26,31,28,33)(29,35,37,40)(32,38,36,39)(1,2)(3,4)(9,11)(10,14)(12,19)(13,18)(15,22)(16,17)(20,23)(21,24)(25,28,30,26)(27,31,34,33)(29,36,37,32)(35,38,40,39)(9,12,13,21)(10,15,16,20)(11,19,18,24)(14,22,17,23)(25,29,30,37)(26,32,28,36)(27,35,34,40)(31,38,33,39)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.