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