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