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