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