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