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