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