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