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