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