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