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