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