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)(11,20)(12,14)(13,23)(15,17)(16,21)(18,24)(19,22)(25,26,31,33)(27,34,30,32)(28,29,38,40)(35,36,37,39)(1,3,5,8)(2,6,4,7)(9,11,15,21)(10,16,17,20)(12,22,24,13)(14,23,18,19)(25,27,31,30)(26,32,33,34)(28,37,38,35)(29,36,40,39)(10,17)(11,21)(12,24)(19,23)(25,28)(26,29)(27,35)(30,37)(31,38)(32,39)(33,40)(34,36) involution — undirected(1,2,5,4)(3,6,8,7)(9,12)(10,18)(11,22)(13,21)(14,17)(15,24)(16,19)(20,23)(25,29)(26,28)(27,36)(30,39)(31,40)(32,37)(33,38)(34,35)(1,4,5,2)(3,7,8,6)(9,13,15,22)(10,19,17,23)(11,12,21,24)(14,20,18,16)(25,28)(26,29)(27,37)(30,35)(31,38)(32,36)(33,40)(34,39)(9,14,15,18)(10,12,17,24)(11,23,21,19)(13,16,22,20)(25,30,31,27)(26,32,33,34)(28,37,38,35)(29,39,40,36)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.