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