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