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