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