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