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)(11,12)(13,17)(14,15)(16,20)(18,19)(21,22)(23,24)(25,26,31,35)(27,32,30,34)(28,33,39,29)(36,38,37,40)(1,2,4,6)(3,5,8,7)(10,15)(11,16)(17,24)(18,21)(25,27,31,30)(26,32,35,34)(28,37,39,36)(29,38,33,40)(1,2)(3,5)(4,6)(7,8)(10,15)(11,16)(17,24)(18,21)(25,28,31,39)(26,33,35,29)(27,36,30,37)(32,38,34,40)(1,3,4,8)(2,5,6,7)(9,11,14,16)(10,12,15,20)(13,21,23,18)(17,22,24,19)(25,28)(26,29)(27,37)(30,36)(31,39)(32,38)(33,35)(34,40)(9,12)(10,16)(11,15)(13,22)(14,20)(17,18)(19,23)(21,24)(25,29)(26,28)(27,38)(30,40)(31,33)(32,37)(34,36)(35,39) involution — undirected(9,13,14,23)(10,17,15,24)(11,18,16,21)(12,19,20,22)(25,30,31,27)(26,34,35,32)(28,37,39,36)(29,38,33,40)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.