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