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