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