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)(19,23)(21,24)(25,26,30,31)(27,34,32,28)(29,37,40,33)(35,36,38,39)(2,3)(6,7)(9,10,13,14)(11,16,15,12)(17,18,20,22)(19,21,23,24)(26,31)(27,32)(33,37)(35,38)(4,8)(6,7)(10,14)(12,16)(25,27,30,32)(26,28,31,34)(29,38,40,35)(33,39,37,36)(1,3,5,2)(4,6,8,7)(9,11,13,15)(10,12,14,16)(17,19)(18,21)(20,23)(22,24)(25,28)(26,32)(27,31)(29,39)(30,34)(33,35)(36,40)(37,38)(1,4,5,8)(2,6,3,7)(9,12)(10,11)(13,16)(14,15)(25,29)(26,33)(27,35)(28,36)(30,40)(31,37)(32,38)(34,39)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.