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