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