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