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