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