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