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