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