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