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