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