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