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