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