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