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