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