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)(15,20)(16,18)(17,21)(19,22)(23,27)(24,25)(26,28) involution — undirected(2,3)(6,9)(10,11)(13,15,19,16)(14,18,22,20)(17,21,26,28)(23,27,24,25)(1,2,4,3)(13,16,19,15)(14,18,22,20)(17,24,26,23)(21,25,28,27)(1,3,4,2)(13,17,19,26)(14,21,22,28)(15,23,16,24)(18,25,20,27)(5,7,8,12)(6,10,9,11)(13,18,19,20)(14,15,22,16)(17,25,26,27)(21,23,28,24)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.