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