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