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