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