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