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