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