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