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