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