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)(11,22)(12,18)(13,19)(14,30)(15,20)(16,21)(17,24)(23,34)(25,33)(26,32)(27,35)(28,39)(29,36)(31,38)(37,40)(9,11,16,25)(10,17,21,18)(12,15,24,14)(13,26,27,38)(19,34,35,40)(20,33,30,22)(23,28,37,29)(31,39,32,36)(1,3,4,8)(2,5,6,7)(9,12,15,25,16,24,14,11)(10,18,20,33,21,17,30,22)(13,26,29,37,27,38,28,23)(19,32,36,40,35,31,39,34)(9,13,15,29,16,27,14,28)(10,19,20,36,21,35,30,39)(11,23,12,26,25,37,24,38)(17,31,22,34,18,32,33,40)(13,27)(19,35)(23,37)(26,38)(28,29)(31,32)(34,40)(36,39) 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.