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