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