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