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