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