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