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