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