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