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