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