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