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