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