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