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)(25,26,30,31)(27,29,33,39)(28,32,37,40)(34,38,35,36)(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)(26,29)(28,35)(30,33)(31,39)(32,36)(34,37)(38,40)(1,2,6,4)(3,7,5,8)(11,14)(16,18)(19,21)(23,24)(26,31)(27,33)(32,40)(34,35)(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)(26,32)(27,34)(29,38)(30,37)(31,40)(33,35)(36,39)(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)(26,27)(28,36)(30,39)(31,33)(32,35)(34,40)(37,38)(1,5,6,3)(2,7,4,8)(9,14,15,11)(10,18,12,16)(13,21,22,19)(17,24,20,23)(25,27)(26,29)(28,34)(30,33)(31,39)(32,38)(35,37)(36,40)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.