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