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