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