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