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