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