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