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