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