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