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