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