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