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