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