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