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