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)(25,26,31,29)(27,35,37,32)(28,38,39,33)(30,34,36,40)(1,2)(3,4)(5,7)(6,8)(9,11,15,12)(10,16,17,14)(13,20,22,19)(18,21,24,23)(25,27,31,37)(26,32,29,35)(28,36,39,30)(33,40,38,34)(1,3)(2,6)(4,7)(5,8)(10,17)(11,12)(18,24)(19,20)(25,26,31,29)(27,32,37,35)(28,33,39,38)(30,34,36,40)(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)(26,33)(27,36)(29,38)(30,37)(31,39)(32,40)(34,35)(1,4,5,6)(2,3,7,8)(9,13,15,22)(10,18,17,24)(11,19,12,20)(14,21,16,23)(25,29,31,26)(27,35,37,32)(28,33,39,38)(30,34,36,40)(1,3)(2,4)(5,8)(6,7)(9,14)(10,11)(12,17)(13,21)(15,16)(18,19)(20,24)(22,23)(25,30,31,36)(26,34,29,40)(27,28,37,39)(32,33,35,38)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.