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