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