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