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