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)(11,16)(12,24)(13,27)(14,19)(15,20)(17,29)(18,25)(21,35)(22,34)(23,31)(26,40)(28,32)(30,37)(33,39)(36,38)(1,3,5,4)(2,6,8,7)(9,11)(10,16)(12,25)(13,21)(14,22)(15,23)(17,30)(18,24)(19,34)(20,31)(26,39)(27,35)(28,36)(29,37)(32,38)(33,40)(1,3,5,4)(2,7,8,6)(9,12,14,11,15,22,25,23)(10,16,18,24,20,31,19,34)(13,26,28,21,29,36,39,37)(17,30,32,38,27,35,33,40)(1,4,5,3)(2,6,8,7)(9,13,14,28,15,29,25,39)(10,17,18,32,20,27,19,33)(11,21,22,36,23,37,12,26)(16,30,24,38,31,35,34,40)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.