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