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