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