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