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