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