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