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