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