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