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