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