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