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