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)(11,14)(12,16)(13,15)(17,20)(18,21)(19,22)(23,24)(25,26)(27,37)(28,40)(29,39)(30,34)(31,35)(32,36)(33,38) involution — undirected(2,5)(6,8)(9,11)(10,14)(12,18)(13,17)(15,20)(16,21)(19,23)(22,24)(25,27,31,38,32,39,30,28)(26,33,34,37,36,40,35,29)(1,3,4,7)(2,6,5,8)(11,17)(14,20)(18,23)(21,24)(25,28,31,27,32,38,30,39)(26,29,34,33,36,37,35,40)(10,15)(14,20)(16,22)(21,24)(25,29,32,37)(26,27,36,39)(28,34,38,35)(30,40,31,33)(9,12,13,19)(10,16,15,22)(11,18,17,23)(14,21,20,24)(25,30,32,31)(26,34,36,35)(27,28,39,38)(29,33,37,40)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.