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