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