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