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