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