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