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