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