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