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