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