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