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