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