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