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