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