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