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