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