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