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