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