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