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