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