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