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