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)(14,20)(15,24)(17,18)(21,28)(22,26)(23,27)(5,6)(7,11)(8,10)(9,12)(13,14,17,27,19,23,18,20)(15,22,16,26,24,21,25,28)(2,4)(5,7)(6,9)(8,12)(10,11)(13,15,19,24)(14,21,23,22)(16,18,25,17)(20,26,27,28)(7,12)(9,11)(13,16)(14,22)(15,17)(18,24)(19,25)(20,26)(21,23)(27,28) involution — undirected(6,10)(9,11)(13,17,19,18)(14,20,23,27)(15,25,24,16)(21,28,22,26)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.