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