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