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