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