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