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