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