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