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