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