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