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