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