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