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