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