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