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