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