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