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