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