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