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