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