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