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