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