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