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