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