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