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