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