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