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