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