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