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