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