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)(12,20)(13,15)(16,18)(17,21)(19,23)(22,24)(26,30)(28,33)(32,36)(34,38)(3,7)(5,8)(9,11)(10,14)(12,19)(13,18)(15,16)(17,22)(20,23)(21,24)(25,26,31,30)(27,32,37,36)(28,29,33,39)(34,35,38,40)(1,2)(3,5)(4,6)(7,8)(10,15)(11,18)(17,20)(19,24)(25,27,31,37)(26,32,30,36)(28,38,33,34)(29,40,39,35)(1,3)(2,5)(4,7)(6,8)(9,10)(11,16)(12,17)(13,15)(14,18)(19,23)(20,21)(22,24)(25,28)(26,29)(27,34)(30,39)(31,33)(32,35)(36,40)(37,38) involution — undirected(1,2)(3,5)(4,6)(7,8)(9,11)(10,16)(12,19)(13,18)(14,15)(17,23)(20,22)(21,24)(25,29,31,39)(26,33,30,28)(27,35,37,40)(32,38,36,34)(9,12,13,21)(10,17,15,20)(11,19,18,24)(14,22,16,23)(25,30,31,26)(27,36,37,32)(28,39,33,29)(34,40,38,35)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.