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