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