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