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)(11,18)(12,17)(13,19)(14,16)(15,22)(20,21)(23,24)(25,26)(27,31)(28,32)(29,39)(30,34)(33,37)(35,40)(36,38)(1,3,5,8)(2,6,4,7)(9,11)(10,15)(12,20)(13,21)(14,22)(16,18)(17,24)(19,23)(25,27)(26,31)(28,37)(29,36)(30,35)(32,33)(34,40)(38,39)(1,2,5,4)(3,6,8,7)(10,16)(13,17)(15,18)(21,24)(27,35)(29,37)(31,40)(33,39)(9,12,14,19)(10,17,16,13)(11,20,22,23)(15,24,18,21)(25,28)(26,32)(27,29)(30,36)(31,39)(33,40)(34,38)(35,37)(1,4,5,2)(3,7,8,6)(9,11)(10,18)(12,23)(13,21)(14,22)(15,16)(17,24)(19,20)(25,29)(26,33)(27,36)(28,35)(30,37)(31,32)(34,39)(38,40)(9,13,14,17)(10,19,16,12)(11,21,22,24)(15,23,18,20)(25,26)(27,31)(28,38)(29,33)(30,34)(32,36)(35,40)(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.