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