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