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