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