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