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