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