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