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