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