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