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