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