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