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