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