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