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