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