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