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