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