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