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