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)(25,26,31,30)(27,28,35,32)(29,37,38,33)(34,39,40,36)(1,2)(3,6)(4,7)(5,8)(25,27,31,35)(26,32,30,28)(29,34,38,40)(33,39,37,36)(1,3,5,4)(2,6,8,7)(10,15)(11,18)(17,20)(19,24)(25,28,31,32)(26,27,30,35)(29,36,38,39)(33,34,37,40)(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)(26,27)(29,36)(30,35)(31,32)(33,34)(37,40)(38,39)(1,4,5,3)(2,7,8,6)(9,12,14,22)(10,17,15,20)(11,19,18,24)(13,21,16,23)(25,29)(26,33)(27,34)(28,36)(30,37)(31,38)(32,39)(35,40)(9,13,14,16)(10,18,15,11)(12,21,22,23)(17,24,20,19)(25,30,31,26)(27,28,35,32)(29,33,38,37)(34,39,40,36)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.