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