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