One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(6,8)(17,18,21,19)(20,23,24,22)(25,26,30,28)(27,33,34,31)(29,36,37,32)(35,38,40,39)(3,7)(6,8)(10,13)(14,16)(26,28)(27,34)(29,37)(38,39) involution — undirected(1,2,5,4)(3,6,7,8)(9,10)(11,14)(12,13)(15,16)(17,19,21,18)(20,23,24,22)(25,27,30,34)(26,31,28,33)(29,35,37,40)(32,38,36,39)(1,3)(2,6)(4,8)(5,7)(17,20,21,24)(18,22,19,23)(25,28,30,26)(27,31,34,33)(29,36,37,32)(35,38,40,39)(1,4,5,2)(3,8,7,6)(9,11,12,15)(10,14,13,16)(25,29)(26,32)(27,35)(28,36)(30,37)(31,38)(33,39)(34,40)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.