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