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