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