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)(11,18)(12,17)(13,19)(14,16)(15,22)(20,21)(23,24)(25,26,31,28)(27,34,32,29)(30,33,38,36)(35,40,39,37)(1,3,5,8)(2,6,4,7)(9,11)(10,15)(12,20)(13,21)(14,22)(16,18)(17,24)(19,23)(25,27,31,32)(26,29,28,34)(30,35,38,39)(33,37,36,40)(10,16)(13,17)(15,18)(21,24)(27,32)(29,34)(35,39)(37,40) involution — undirected(1,2,5,4)(3,6,8,7)(9,12,14,19)(10,17,16,13)(11,20,22,23)(15,24,18,21)(25,28,31,26)(27,29,32,34)(30,33,38,36)(35,40,39,37)(9,11)(10,18)(12,23)(13,21)(14,22)(15,16)(17,24)(19,20)(25,29)(26,32)(27,28)(30,37)(31,34)(33,39)(35,36)(38,40) involution — undirected(1,4,5,2)(3,7,8,6)(9,13,14,17)(10,19,16,12)(11,21,22,24)(15,23,18,20)(25,30,31,38)(26,33,28,36)(27,35,32,39)(29,37,34,40)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.