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