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