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