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