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