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