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