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