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