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