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