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