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