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)(15,17)(16,20)(18,19)(23,27)(26,28) involution — undirected(6,11)(9,12)(13,15,18,20)(14,16,19,17)(22,25)(26,28)(5,7,10,8)(6,12,11,9)(13,16,18,17)(14,15,19,20)(21,22)(23,26)(24,25)(27,28)(1,2)(3,4)(5,8,10,7)(6,12,11,9)(13,14)(15,16)(17,20)(18,19)(21,23,24,27)(22,26,25,28)(5,9,10,12)(6,8,11,7)(13,17,18,16)(14,15,19,20)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.