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