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