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