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