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