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