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