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