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