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