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